A novel approach to measuring the developmental interactions between working memory and inhibitory control in young children

This pre-registered study examined the development of working memory and inhibitory control in a sample of 144 children aged between 3 and 6 years. Two paradigms - one a version of a spatial conflict task, the other a combined continuous performance test and go/no-go task - were adapted to allow the orthogonal manipulation of working memory and inhibitory demands. This allowed for the simultaneous measurement of these functions within each paradigm, removing concerns of task-specific variance and testing an interactive model of executive function that assumes that working memory and inhibition compete for a shared pool of executive resources. In addition, latent working memory and inhibition variables extracted from the tasks were correlated with parental reports of participants' temperament, including effortful control. The novel experimental tasks successfully and reliably captured developmental and individual differences in working memory and inhibitory control. However, these factors did not interact with one another in an over-additive fashion or correlate meaningfully with parental ratings of effortful control. These findings support the separability of executive functions in this age range while raising important questions about how best to measure the development of executive functioning among young children.